[PATCH v7 03/41] KVM: arm64: Return early from kvm_finalize_sys_regs() if guest has run

[Sascha Bischoff]

If the guest has already run, we have no business finalizing the
system register state - it is too late. Therefore, check early and
bail if the VM has already run.

This change also stops kvm_init_nv_sysregs() from being called once
the RM has run once. Although this looks like a behavioural change,
the function returns early once it has been called the first time.

Signed-off-by: Sascha Bischoff <sascha.bischoff at arm.com>
---
 arch/arm64/kvm/sys_regs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0acd10e50aaba..42c84b7900ff5 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -5659,11 +5659,14 @@ int kvm_finalize_sys_regs(struct kvm_vcpu *vcpu)
 
 	guard(mutex)(&kvm->arch.config_lock);
 
+	if (kvm_vm_has_ran_once(kvm))
+		return 0;
+
 	/*
 	 * This hacks into the ID registers, so only perform it when the
 	 * first vcpu runs, or the kvm_set_vm_id_reg() helper will scream.
 	 */
-	if (!irqchip_in_kernel(kvm) && !kvm_vm_has_ran_once(kvm)) {
+	if (!irqchip_in_kernel(kvm)) {
 		u64 val;
 
 		val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;
-- 
2.34.1